This disclosure relates to testing of fiber optic communication lines, and more particularly to the inspection of the end surfaces of fiber optic cables.
Current fiber inspection probes (or cameras) in the market use one fixed light (for example, a LED or light bulb) that shines light through a prism onto the fiber end-surface for inspection. The detection of defects on fiber end-surface can be dependent on the angle of the single light source provided with a typical fiber inspection tool. With a typical single light source tool, in a particular case it may be that a scratch cannot be detected from first inspection, but, upon a user manually rotating or otherwise maneuvering the fiber to get different angles of light falling on the fiber end, scratches that might not be visible at first, may come into view.
To inspect dirt or chirp of fiber connector-end, a small fiber scope (or probe) is typically used. In machine vision systems, light source is one of the key factors. Some of the big scope stations use fiber ring light sources and other small scopes use a LED light next to the scope. If the light shades from center or perimeter like fiber ring light source, some of the defects (dirt, chirp, or scratch) are difficult to find because defects can be obscured by shadows. On the other hand, if the light is from side, the other half of the fiber-end becomes dark because the fiber-end is not a straight plane but instead has curvature. Thus, some experienced technicians rotate the fiber to inspect the other side of the fiber end. However, this method does not work with angled connectors and with automated fiber-end inspection system using machine vision. Also, requiring such manual movement to accomplish testing adds a factor of operator skill to the reliability of the test results, which is undesirable.